1. Field of the Invention
The present invention relates to a connection of terminals to a communication network through an exchange for connecting with an external communication network, and more particularly to a communication system capable of automatically processing a connection setting for connecting the terminals such as a telephone and a computer to the external communication network, and a connection setting method and a connection setting program of the exchange and the terminals.
2. Description of the Related Art
Recently, there has evolved wide usage of a system having telephone terminals, personal computer terminals, and the like connected and used in a mixed way on the Internet.
The devices connected on the Internet are distinguished from each other by their IP addresses. Since a plurality of terminals of different types and different manufacturing companies are connected on the same network, it is necessary to set each IP address and extension number as the identification information of each terminal when using these terminals on the Internet.
Hitherto, there have been two methods for obtaining the IP address of each terminal; a manual setting method and an automatic setting method in which use is made of a DHCP (Dynamic Host Configuration Protocol Server).
For example, in the automatic technique of setting by using the DHCP server, the DHCP server built in an exchange assigns each IP address to the terminals on a network and at the same time notifies the terminals of the IP address.
However, the conventional setting method for connecting a terminal to a communication network has the following problems.
At first, it is not always possible to obtain the expected IP address in the case of automatic setting, and there is a problem that an IP address which is different from the previous IP address may be assigned in the case of a restart. For example, when the IP address of a terminal connected to an exchange is changed by a restart, the exchange regards the terminal as a different terminal and the terminal cannot use the information previously set to it, such as the telephone book information. Further, acquisition of IP address by the manual setting is very troublesome.
Secondly, since there is no means of knowing the IP address of a communication party in the general communication method, it is necessary to enter the IP address of the communication party by hand. In order to automatically obtain the IP address of a communication party and establish a communication, it is necessary to set a special server and a client, or previously register the IP address of the communication party in the DHCP server by hand. Therefore, in order that a terminal of an exchange knows the IP address of a destination exchange, it is necessary to enter the IP address of the destination exchange into the terminal by hand, or it is necessary to previously enter the IP address of the destination exchange in the DHCP server by hand.
Thirdly, the data flowing on the Internet arrives at the communication party in various orders depending on the state of network congestions or physical distance between the communication parties, and therefore, it is difficult to foresee the arriving order. For example, when a plurality of exchange terminals are located in an office and they are switched on at the same time, it is impossible to foresee the order of the data being registered in an exchange.
Therefore, for example, when a terminal of the extension number X is to be located at the seat of a staff member A and a terminal of the extension number Y is to be located at the seat of a staff member B, it is necessary on the exchange side to set MAC addresses of the terminals for assigning the extension numbers X and Y. Here, the MAC address is formed by the alphanumeric letters of 12 digits, and a user's manual task of entering the MAC addresses of the respective terminals is very troublesome.